| package main |
| |
| func Allocate(store Storage, mac string) (string, error) { |
| // Check to see if an IP address is already allocated and if so just |
| // return that value |
| ip, err := store.Get(mac) |
| if err != nil { |
| return "", err |
| } |
| |
| if ip != "" { |
| return ip, nil |
| } |
| |
| // This MAC does not already have an IP assigned, so pull then next |
| // one off the available queue and return it |
| ip, err = store.Dequeue() |
| if err != nil { |
| return "", err |
| } |
| err = store.Put(mac, ip) |
| if err != nil { |
| store.Enqueue(ip) |
| return "", err |
| } |
| return ip, nil |
| } |
| |
| func Release(store Storage, mac string) error { |
| ip, err := store.Remove(mac) |
| if err != nil { |
| return err |
| } |
| |
| if ip != "" { |
| err = store.Enqueue(ip) |
| if err != nil { |
| return err |
| } |
| } |
| return nil |
| } |